During the manufacturing of can bodies, after the body has left the welding machine, it is directly further processed or the applied seam cover is burned in. For subsequent operations the lying body is normally brought into the standing, vertical position. Body lifting device are known, which accomplish this by means of a magnetic field. In these cases lifting is normally carried out about the front edge of the body, such that the rear section of the body moves upward. Known magnetic body lifting devices work with magnetic cases arranged on both sides of the transport path of the body.
An example for such a lifting device is a magnetic body lifting device of the company O. S. Walker Magnetics, USA. With this body lifting device the body is lifted about its front edge or the front edge is rotated or tilted, respectively, such that the body is lifted by its rear section. By arranging magnet elements, which consist of individual magnets arranged inside a closed case, one after the other, a magnetic field corresponding to a single large magnet is generated. By using two magnet cases on both sides of the transport path of the bodies, the body is centered, such that the risk of scratches on the body paint is reduced. This solution works for various body diameters and heights and is therefore a universal solution in case the bodies are lifted by their rear sections.
A further magnetic body lifting device is known from the company NSM Magnettechnik GmbH, Germany and is intended for dedicated manufacturing lines in case of which the body height and the body diameter are substantially predefined. This body lifter works with few magnets which are combined as individual magnet bars arranged in a special way, being arranged in closed magnet cases on both sides of the transport path of the bodies in a precisely specified position. The arrangement of the magnet bars is designed in such a way that this body lifter is built either for lifting via the front edge of the body or for lifting via the trailing edge of the body.
A further body lifting device is disclosed in patent application CH 706 991 A1. This device also uses magnet cases, like the already mentioned devices, which are arranged on both sides of the transport path of the bodies.
Usage of magnet cases on the side of the transport path produce a number of more or less pronounced disadvantages. One disadvantage consists in the fact that an increased risk of contact between the magnet cases and the transported bodies exists, potentially leading to damage of the bodies. Furthermore, such magnet cases may be difficult to mount and to adjust. In this context they have the disadvantage that free viewing of the interior of the device is blocked by their position, such that access to the device is made difficult. Furthermore, the trajectory or the lifting process, respectively, of the bodies cannot be supervised or can only be supervised hardly, such that later adjustments of the device are complicated.